Control module for an ion implanter

Abstract

A control module for an ion implanter having a power supply, the power supply comprising: an electricity generator HT having its positive pole connected to ground; a first switch SW 1 having its first pole connected to the negative pole of the generator HT and having its second pole connected to the outlet terminal S of the power supply; and a second switch SW 2 having its first pole connected to the outlet terminal S and having its second pole connected to a neutralization terminal N. The control module also comprises a current measurement circuit AMP for measuring the current that flows between the second pole of the second switch SW 2 and the neutralization terminal N.

The invention claimed is: 
     
       1. A control module for an ion implanter having a power supply, the power supply comprising:
 an electricity generator (HT) having its positive pole connected to ground; 
 a first switch (SW 1 ) having its first pole connected to the negative pole of said generator (HT) and having its second pole connected to the outlet terminal (S) of the power supply; and 
 a second switch (SW 2 ) having its first pole connected to said outlet terminal (S) and having its second pole connected to a neutralization terminal (N); 
 the control module being characterized in that it includes a current measurement circuit (AMP) for measuring the displacement current that flows between the second pole of said second switch (SW 2 ) and said neutralization terminal (N). 
 
     
     
       2. A control module according to  claim 1 , characterized in that said neutralization terminal (N) is connected to ground. 
     
     
       3. A control module according to  claim 1 , characterized in that said neutralization terminal (N) is connected to the positive pole of a voltage source having its negative pole connected to ground. 
     
     
       4. A control module according to  claim 1 , characterized in that said current measurement circuit (AMP) is a coil surrounding the cable connecting the second pole of said second switch (SW 2 ) to said neutralization terminal (N). 
     
     
       5. A control module according to  claim 1 , characterized in that said current measurement circuit (AMP) comprises a measurement resistor (Rm) connected between the second pole of the second switch (SW 2 ) and said neutralization pole (N), an integration capacitor (Ci) in parallel with said measurement resistor (Rm), and a voltage measuring circuit (U) likewise in parallel with the measurement resistor (Rm). 
     
     
       6. A control module according to  claim 1 , characterized in that it further includes a regulation capacitor (Cr) arranged between the negative pole of said generator (HT) and ground. 
     
     
       7. A control module according to  claim 1 , characterized in that it includes a member (CUR) for estimating the power supply current delivered by said generator (HT) and it further includes a control circuit (CC) for estimating the implantation current by differentiating said power supply current and said displacement current (AMP). 
     
     
       8. A control module according to  claim 1  characterized in that it includes a member (CUR) for estimating the implantation current delivered by said generator (HT) and receiving a disturbance current delivered by a secondary electron detector (DES), and it further includes a control circuit (CC) for estimating the ion current by subtracting said displacement current (AMP) and said disturbance current from said power supply current. 
     
     
       9. A control module according to  claim 8 , characterized in that said control circuit (CC) also receives the proportion of a predetermined ion species as determined by a spectrometer (SPC), and said control circuit (CC) allocates said proportion to said ion current in order to estimate the implanted dose. 
     
     
       10. An ion implanter provided with a control module according to  claim 1  and characterized in that it has a substrate carrier platen (PPS) with the outlet terminal (S) of said power supply (PS) connected to said substrate carrier platen (PPS).